/*
 * $Id: FontFormatWriter.java,v 1.6 2004/01/28 11:44:08 eed3si9n Exp $
 * 
 * $Copyright: copyright (c) 2003, e.e d3si9n $
 * $License: 
 * This source code is part of DoubleType.
 * DoubleType is a graphical typeface designer.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This Program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * In addition, as a special exception, e.e d3si9n gives permission to
 * link the code of this program with any Java Platform that is available
 * to public with free of charge, including but not limited to
 * Sun Microsystem's JAVA(TM) 2 RUNTIME ENVIRONMENT (J2RE),
 * and distribute linked combinations including the two.
 * You must obey the GNU General Public License in all respects for all 
 * of the code used other than Java Platform. If you modify this file, 
 * you may extend this exception to your version of the file, but you are not
 * obligated to do so. If you do not wish to do so, delete this exception
 * statement from your version.
 * $
 */
 
package org.doubletype.ossa.truetype;

import java.io.*;
import java.util.*;

/**
 * @author e.e
 */
public class FontFormatWriter {
	protected DataOutputStream m_buffer;
	protected ByteArrayOutputStream m_bytes;
	private int m_offset;
		
	public FontFormatWriter() {
		init();
	}
	
	protected void init() {
		m_bytes = new ByteArrayOutputStream();
		m_buffer = new DataOutputStream(m_bytes);
		m_offset = 0;
	}
	
	public void write() throws IOException {
	}
	
	public byte[] toByteArray() {
		return m_bytes.toByteArray();
	}
	
	/**
	 * Size of buffer in bytes.
	 * @return size of buffer in bytes.
	 */
	public int size() {
		return m_bytes.size();
	}
	
	public void reset() {
		m_bytes.reset();
	}
	
	protected void writeFixed32(double a_value) throws IOException {
		final int k_denom = 16384;
		
		short mantissa = (short) Math.floor(a_value);
		int fraction = (int) ((a_value - mantissa) * k_denom);
		if (fraction > k_denom) {
			fraction = 0;
			mantissa++;
		} // if
		
		m_buffer.writeShort(mantissa);
		m_buffer.writeShort(fraction);
	}
	
	protected void writeUInt16(int a_value) throws IOException {
		writeInt16((short) (0xffff & a_value));
	}
	
	protected void writeInt16(int a_value) throws IOException {
		m_buffer.writeShort((short) a_value);
	}
	
	protected void writeFWord(int a_value) throws IOException {
		writeInt16(a_value);
	}
	
	protected void writeUFWord(int a_value) throws IOException {
		writeUInt16(a_value);
	}
	
	protected void writeUInt32 (long a_value) throws IOException {
		writeInt32((int) (0xffffffff & a_value));
	}
	
	protected void writeInt32(int a_value) throws IOException {
		m_buffer.writeInt(a_value);
	}
	
	protected void writeUInt8(int a_byte) throws IOException {
		m_buffer.writeByte(a_byte);
	}
	
	protected void writeTag(String a_value) throws IOException {
		String s = a_value + "    ";
		
		int i;
		for (i = 0; i < 4; i++) {
			writeUInt8(s.charAt(i));
		} // for i
	}
	
	protected void writeLongDateTime(Date a_date) throws IOException {
		long sec = a_date.getTime() / 1000;
		sec += (1970 - 1904) * 365 * 24 * 60 * 60;
		m_buffer.writeLong(sec);	
	}
	
	protected String getTag() {
		throw new RuntimeException("unimplemnted call to getTag");
	}
	
	protected long getCheckSum() {
		long retval = 0;
		byte [] bytes = toByteArray();
		
		for (int i = 0; i < bytes.length / 4; i++) {
			long n = 0;
			for (int j = 0; j < 4; j++) {
				n += bytes[4 * i + j] << ((4 - j) * 8);	
			} // for j
			retval += n;
		} // for i
	
		return retval;
	}
	
	protected void pad() throws IOException {
		int align = 4;
		int numOfPad = align - toByteArray().length % align;
		if (numOfPad == align)
			return;
		
		int i;
		for (i = 0; i < numOfPad; i++) {
			writeUInt8(0);
		} // for i
	}
	
	public int getOffset() {
		return m_offset;
	}
	
	public void setOffset(int a_value) {
		m_offset = a_value;
	}
}
